GLE. Ground Level Enhancements

[hamateur 1953]

These events occur during most solar cycles and are recorded as such should there be simultaneous increased neutron counts at two terrestrial locations as I understand it.
what I don’t understand is the apparently large differences of MEV or energy that it seems to take to “ make the case”. I have read as low as 116 MEV  recently and read elsewhere as high as 500 MEV.   No doubt during high solar flux we have more protection from these as typical neutron counts plunge typically during solar max but 116 just seems a bit low to me.   Anyone know more??  Tnx. Mike.